Process of preparing 2-(or 3-) chloro-quinizarine



Patented Jan. 10, 1928. g

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PROCESS OF PREPARING fi-(OE 3-) UHLOEU-Q'UINIZARTNE.

lto Drawing.

an The reaction proceeds according to this equation particularly withtemperatures below 200 U; and when sulfuric acid below 100% is used Atabout/200 G.v using sulfuric acid at 100% strength or turning suli'uricas acid, ring closing to an 'anthraqulnone derivative talres lace and 1molecule oi hydro- 1 chloric acid is eliminated and replaced by a Ihydronyl group, the end product being 2- (or 3-)-chloro-1,d-dihydrorryanthraquinone.

an The reaction proceeds evidently according to I the tollewingequations:

r or 1 i The reactions as indicated "by equations v (2) and (3) seem tobe simultaneous, which is in accordance with the well known fact thathalogenatoms are not easily removed in benzene derivatives, whereas inanthraqumone derivatives they become very mobile. It is evident thatsince the structural formula for the end product is symmetrical about ahorizontal axis except for the chlorine atom,

the product may be called either 2- or 3- red color, and in 2% 3 isfiltered ofi tained is boiled up acid for about Appiicatien filedNovember 2, 1025. term]. Ito. 60,420.

ehloro-l, l-dihydroxyanthraquinone, the two names being in fact for thesame chemical compound.

The 2-(or 3-) chloro-lAl-dihydroxyanthraquinone thus obtained is anorangecolored -powder having a melting point or 235-236" C. lit ispractically insoluble in water and dilute acids, slightly soluble inalcohol, fairly soluble in benzol and toluol,- and readily soluble inaniline and its homelogues. it dissolves in sulfuric acid, giving asolution having a bright orangecaustic soda solution giving a brightpurple solution which becomes slightly bluer on further dilution.

While ll do not desire to limit my invention to any particularprocedure, the "lollowing examples, in which parts by weight are given,will serve to illustrate my preferred methods 2 y Ema/rm Ze I..-50 partsoi 3, 1-dichlorophenol, aving a melting point oi 641 U, is added to 050parts at 100% sulfuric acid together with 55 parts oil boric acid and150 parts at phthalie anhydride. The reaction mixture is well agitatedand the temperature is gradually raised to hie-200 0., where it is keptfor 4t hours. The mixture gradually assumes a bright red color, whichecomes more intense as the reaction proceeds. litter t hours oi heating,no appreciable increase in the intensity of theet color should beapparent and the reaction is then regarded as finished. The mass is nowcooled to 100 C, and gradually poured into 19000 parts oi cold water..The product oi the reaction, which is thereby precipitated,

and the filter cake thus chin 3000 parts oi water containing parts ofBe. hydrochloric hour, The precipitate is again filtered, washed free ofacid, and dried in a suitable drier, preferably under vacuum...

235-236 C. However, for use in manufacturing dyestufls, the crudeproduct is sufficiently pure.

Example [l.--10 parts of 3,4-dichlorophenol having a melting point of64G. is added to 180 parts sulfuric acid containing 5% free sulfuric acidanhydride, together with 30 parts of phthalic acid anhydride and 11parts of boric acid. The mixture is Well agitated and the temperaturegradually raised to 200 C. The reaction mixture gradually assumes abright red color which becomes more intense as the reaction proceeds.After 3 hours of heating, no appreciable increase in the intensity ofthe color is apparent and the reaction is then regarded as finished. Themass is then cooled to 50 C. and gradually poured into 3600 parts ofcold Water. The 2-chloroor 3-chloro-1,4 dihydroxy anthraquinone 2- (or3-) chloroquinizarine is thereby precipitated. It is filtered off andthe filter cake further treated in a similar way as given in Example I.

I am aware that numerous details of the process may be varied through awide range without departing from the spirit of this invention, and I donot desire limiting the patent granted hereon other than necessitated bythe prior art. i

I clalm as my invention:

1. The process of preparing 2-(or 3-) chloro-quinizarine by condensing3,4-dichlorophenol with phthalic anhydride in the presence ofconcentrated sulfuric acid and boric acid.

2. The process of preparing chloro-quinizarine by condensing 3,4?diChl0-rophenol with phthalic anhydride in the presence of sulfuric acidcontaining free sulfuric anhydride and boric acid.

3. The process of preparing 2-(01 3-) chloro-quinizarine, whichcomprises condensing 3,4-dichlorophenol with phthalic anhydride in thepresence of concentrated sulfuric acid and boric acid and hydrolyzingthe condensation product so formed without isolating the same from thecondensation mass to obtain chloro-quinizarine directly in a high stateof purity.

4. The process of preparing 2-(or 3-) chloro-quinizarine, whichcomprises condensing 3,4-dichlorophenol with phthalic anhydride in theresence of concentrated sulfuric acid and oric acid at approximately 200C. for 3 to 4 hours, cooling the condensation mass and pouring the sameinto a relatively large quantity of water, whereby a precipitation ofchloro-quinizarine occurs.

In testimony whereof I have hereunto subscribed my name.

" IVAN GUBELMANN.

